The following code is getting all terms and see if any one of them is checked or not. If any term is checked a form should show under the selected checkbox with email, the username(auto-generated) and password(auto-generated), and admin should be available to submit each form which will create a user for a specific term.

The problem is The form is being submitted to options.php which I have to submit checkboxes in the options table

<div class="wrap">
            <?php screen_icon(); ?>
            <h2>Subdomain Settings</h2>           
            <form method="post" action="options.php">
            <?php
                // This prints out all hidden setting fields
                settings_fields( 'subdomain_option_group' );   
                do_settings_sections( 'subdomain-admin' );
                submit_button(); 
            ?>
            </form>
        </div>

        $selected = $this->options;
        $terms = $GLOBALS['wpdb']->get_results( "SELECT * FROM wp_terms", OBJECT );
//      $terms = get_terms();
//      echo plugin_dir_url( __FILE__ ) . 'subdomain-users.php';
        foreach($terms as $term) {
            ?><div class="wrap"> <?php
                ?> <input id="in-category-<?php echo $term->term_id ?>" type="checkbox" name="post_category[]" <?php echo in_array($term->term_id, $selected['subdomain_cat']) ? "checked" : ""; ?> value="<?php echo $term->term_id; ?>" > 
                <label for="in-category-<?php echo $term->term_id ?>"> <?php echo $term->name; ?></label>
                <?php
                if(in_array($term->term_id, $selected['subdomain_cat'])) {
                    ?> <div style="margin-bottom: 25px;"> <?php
                        ?> <form method="post" action=""><?php
                        ?> <h2><?php echo "Category : ".$term->name.'<br/>'; ?></h2> <?php
                        ?> <input type="email" placeholder="Enter Your Email:" name="email"> <?php
                        ?> <input required type="text" placeholder="Enter Your Name:" value="<?php echo $this->generate_user_name($term->name); ?>" name="name"> <?php
                        ?> <input required type="text" value="<?php echo $this->randomPassword() ?>" placeholder="Enter Your Password:" name="password"> <?php
                        ?> <input type="submit" name="user_save" id="user_save" class="button button-primary" value="Save User"><?php
                        ?> </form> <?php
                    ?> </div> <?php
                }
            ?></div><?php
            
        }

Please let me know how do I submit this form to create user for each term And I want to add a role and permission too which will allow the created user to select only the relevant term(category) for post and he will be author for only that category.

Thanks